Smart current system for dynamically varying the operating current of a frequency source in a receiver

ABSTRACT

A system capable of varying the operating current of at least one frequency source in the receiver of a communication device in response to the presence of an undesired signal within a frequency band of signals received at the receiver. The system may include a condition signal indicative of the presence of an undesired signal within a frequency band of signals received at a receiver and a controller that adjusts a frequency source responsive to the condition signal.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] This invention relates to radio frequency transceivers, and, inparticular, to a system for varying the operating current of frequencysources within the transceiver.

[0003] 2. Related Art

[0004] In today's society the presence and utilization oftelecommunication systems is increasing at a rapid pace. Wireless andbroadband systems and infrastructures continue to grow. As a result anincreasing number of electronic signals are produced and propagatedthrough an increasingly crowded free-space (i.e., air and space) andguided mediums (i.e., such a wire, cable, microwave, millimeter andoptical waveguides utilized by telephone, cable and fiber-opticsystems). As the number of propagated electronic signals increases inthese crowded mediums so does the probability of signal interference andthe need for bandwidth efficiency.

[0005] As such, modern communication devices are designed to operate inspecific frequency bands in which the communication devices transmit andreceive electronic signals at specific predefined frequencies that donot interfere with other communication devices that are transmitting andreceiving other electronic signals at other specific predefinedfrequencies. These designs require that a communication device have anaccurate frequency source for accurately demodulating the receivedelectronic signals without also receiving an undesired electronicsignal. Typically, the accuracy of the frequency source is designed toachieve high sensitivity performance in the communication device.

[0006] Frequency sources are typically non-ideal and are generallycharacterized by a parameter defined as phase noise. Phase noisequantifies the noise in the frequency source at frequencies other thanthe frequency of interest. In the presence of strong undesired signals(also known as interfering or jamming signals) within the received bandof interest, the phase noise of the frequency source output mixes withthe undesired signal and is down-converted to an intermediate frequency(IF) in a super heterodyne implementation of a receiver. The processresults in an increase in the in-band noise within the receiverbandwidth and degrades the signal to noise ration (SNR). As such, thecurrent consumption in the typical oscillator core circuits included ina frequency source increases to maintain the phase noise of thefrequency source to an adequately low level so as to not degrade theperformance of the receiver.

[0007] Frequency sources are typically electronic devices that mayinclude a number of components such as transistors, circuits andfrequency reference sources such as crystals. These components requirepower and thus draw significant amounts of current. As a result, afrequency source requires a high amount of power to achieve highaccuracy and produce a highly precise frequency output. The powerrequirement translates into the frequency source drawing high amounts ofcurrent for high accuracy.

[0008] Unfortunately, energy is expensive and at times in short supply.Modern communication devices such as radios, televisions, stereos andcomputers consume a significant amount of power that translates intoexpensive electrical costs. Additionally, current mobile wirelessdevices such as cellular telephones, portable televisions, portableradios, personal communication devices, pagers and satellites operate onbattery power and thus have limited battery time. Limited battery timetranslates into limited continuous operation time. Therefore, there is aneed for a system that reduces the amount of power required by thefrequency source of a communication device.

SUMMARY

[0009] This invention provides a receiver capable of varying theoperating current of at least one frequency source in the receiver of acommunication device in response to the presence of an undesired signalwithin a frequency band of signals received at the receiver. As anexample of operation the system would determine the presence of anundesired signal within a frequency band of signals received at areceiver and adjust a frequency source responsive to the presence of theundesired signal.

[0010] As an example implementation of this system architecture, thesystem may include a condition signal indicative of the presence of anundesired signal within a frequency band of signals received at areceiver and a controller that adjusts a frequency source responsive tothe condition signal. The controller, responsive to the presence of theundesired signal, may dynamically adjust the operating current of thefrequency source. Additionally, the operating current of the frequencysource may be set at a default level optimized for the presence of theundesired signal. The operating current of the frequency source may thenbe reduced from the default level in the absence of the undesiredsignal.

[0011] Other systems, methods, features and advantages of the inventionwill be or will become apparent to one with skill in the art uponexamination of the following FIGURES. and detailed description. It isintended that all such additional systems, methods features andadvantages be included within this description, be within the scope ofthe invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The components in the figures are not necessarily to scale,emphasis instead being placed upon illustrating the principals of theinvention. In the figures, like reference numerals designatecorresponding parts throughout the different views.

[0013]FIG. 1 is a block diagram of an example implementation of a SmartCurrent System “SCS” within a communication device.

[0014]FIG. 2 is a block diagram of the transceiver block of the SCSshown in FIG. 1.

[0015]FIG. 3 is a plot of signal amplitude versus frequency showing theinterference of an undesired signal within the frequency band ofreceived signals at the transceiver block of FIG. 2.

[0016]FIG. 4 is a flow chart illustrating the process performed by theSCS of FIG. 1 controlling at least one frequency source.

[0017]FIG. 5 is a flow chart illustrating the process performed by theSCS 102 of FIG. 1 in controlling multiple frequency sources.

[0018]FIG. 6 is a block diagram of another example implementation of theSCS.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019]FIG. 1 is a block diagram of a communication device 100. Thecommunication device 100 includes an example implementation of a SmartCurrent System “SCS” 102 within a transceiver 104, an undesired signaldetector 106 and a power source 108. The SCS 102 includes a controller110 and a frequency source 112. The transceiver 104 is connected to theundesired signal detector 106 and the power source 108. The controller110 is connected to the frequency source 112, via signal path 114,undesired signal detector 106, via signal path 116, and power source 108via signal path 118.

[0020] The transceiver 104 is a standard type communication device thatincludes both a receiver (not shown) to receive signals within a firstfrequency band (i.e., bandwidth), and transmitter (not shown) totransmit other signals within a second frequency band. It is appreciatedby those skilled in the art that the first frequency band and secondfrequency band may be either different frequency bands or the samefrequency band based on the desired application of the transceiver 104.The transceiver 104 may be a transceiver in a wireless device (such as acellular telephone, two-way radio, two-way pager, a satellite, personaldigital assistant “PDA” and other personal communication device) or amodem (such as plain old telephone system “POTS,” generic digitalsubscriber line “XDSL,” cable or fiber optic communication device).Additionally, it is also appreciated, that the SCS 102 may also utilizea receiver (not shown) instead of the transceiver 104. In this case, thereceiver may be a receiver in any one-way communication device such as atelevision, one-way radio, one-way pager, one-way PDA, or other similardevice.

[0021] The undesired signal detector 106 detects the presence of anundesired signal (also known at times as a “jammer” signal) within thefrequency band of signals received at the receiver (not shown) of thetransceiver 104 and produces a condition signal indicative of thepresence of the undesired signal. The undesired signal detector 106 maybe designed for utilization of the SCS 102 in a specific fieldenvironment. Typically within a given field environment, the probabilityfunction of the occurrence of undesired signals within the frequencyband of signals received at the receiver (not shown) indicates that theoccurrence of these types of signals are less than continuous. Anexample of the signal detector 106 in a wireless telephone applicationincludes the Mobile Station Modem integrated circuit produced byQualcomm Inc., of San Diego, Calif.

[0022] The controller 110 is any type of control device that may beselectively implemented in software, hardware (such as a computer,processor, micro controller or the equivalent), or a combination ofhardware and software. The controller 110 receives the condition signalfrom the undesired signal detector 106 via signal path 116. Thecontroller 110 varies and/or adjusts the frequency source 112, viasignal path 114, in response to the condition signal from the undesiredsignal detector 106. The controller 110 may vary and/or adjust thefrequency source 112 by varying and/or adjusting a current supplied tothe frequency source 112 from the power source 108. As an example, whenthe controller 110 receives the condition signal indicating the presenceof an undesired signal, the controller 110 increases the amount ofcurrent supplied from the power source 108 to the frequency source 112to a current level above a predetermined current level. When thecontroller 110 later receives the condition signal indicating that thereare no more undesired signals, the controller 110 then decreases theamount of current supplied from the power source 108 to the frequencysource 112 back to the predetermined current level. Additionally, if therelative strength of the undesired signal relative to the strength ofthe other received signals is available, the controller 110 may set theamount of current supplied from the power source 108 to the frequencysource 112 to a second predetermined current level based on a look uptable (not shown) or processor unit (not shown) located either in orexternal to the controller 110.

[0023] As an example implementation in a code division multiple access“CDMA” system, the controller 110 may utilize a total received signalstrength indicator (also known as “RSSI”) to measure the total powerwithin the receiver bandwidth. The RSSI produces an output that isgenerally a combination of the signal, noise and interfering products.However, after demodulation of the received signal by de-spreadingoperation in the transceiver 104, the signal strength is typically ameasure of only the received power only. As such, the relative measureof the undesired signal (i.e., jammer) strength may be obtained bycomparing the output of the RSSI with the signal strength afterdemodulation.

[0024] The power source 108 is a standard power supply. In wirelessapplication the power source 108 may be a battery in a cellulartelephone or radio. In non-wireless applications the power source 108may be a power supply connected to a standard power line.

[0025]FIG. 2 illustrates an example implementation of a transceiver 104block shown in FIG. 1 connected to an antenna 200. The transceiver 104has multiple frequency sources that may be varied, set and/or adjustedby the controller 110. The transceiver 104 includes a receiver portion202, transmitter portion 204, duplexer 206, a first frequency source 208and controller 110. The receiver portion 202 and transmitter portion 204are both electrically connected to the duplexer 206. The duplexer 206allows simultaneous reception and transmission over antenna 200 by boththe receiver portion 202 and transmitter portion 204.

[0026] The first frequency source 208 is electrically connected to thecontroller 110. The first frequency source 208 is a standard frequencydevice such a local oscillator, frequency synthesizer, or other similarfrequency device.

[0027] The receiver portion 202 includes a low noise amplifier “LNA”210, bandpass filter “BPF” 212, mixer 214, intermediate frequency “IF”filter 216, automatic gain control “AGC” amplifier 218, and quadraturedemodulator 220. The LNA 210 is electrically connected to the duplexer206 and BPF 212. The BPF 212 is electrically connected to mixer 214.Mixer 214 is electrically connected to the first frequency source 208and IF filter 216. The IF filter 216 is electrically connected to AGC218. The AGC is electrically connected to quadrature demodulator 220.The quadrature demodulator 220 is electrically connected to thecontroller 110.

[0028] The transmitter portion 204 includes a quadrature modulator 222,AGC amplifier 224, IF filter 226, mixer 228, image reject BPF 230,pre-driver amplifier 232, BPF 234 and power amplifier 236. Thequadrature modulator 222 is electrically connected to the controller 110and AGC amplifier 224. The AGC amplifier 224 is electrically connectedto IF filter 226. The IF filter 226 is electrically connected to mixer228. Mixer 228 is electrically connected to both the first frequencysource 208 and image reject BPF filter 230. Image reject BPF filter 230is electrically connected to pre-driver amplifier 232. The pre-driveramplifier 232 is electrically connected to BPF filter 234. BPF filter234 is electrically connected to power amplifier 236. The poweramplifier 236 is electrically connected to duplexer 206.

[0029] The quadrature demodulator 220 includes an in-phase (i.e., Ichannel) mixer 238, out-of-phase (i.e., quadrature “Q” channel) mixer240, 90° phase shifter 242 and second frequency source 244. The AGCamplifier 218 is electrically connected to both the in-phase mixer 238and out-of-phase mixer 240. The 90° phase shifter 242 is electricallyconnected to the in-phase mixer 238, out-of-phase mixer 240 and thesecond frequency source 244.

[0030] The quadrature modulator 222 includes an in-phase mixer 246,out-of-phase mixer 248, 900 phase shifter 250, third frequency source252 and combiner 254. The AGC amplifier 224 is electrically connected tocombiner 254. Combiner 254 is electrically connected to both in-phasemixer 246 and out-of-phase mixer 248. The 90° phase shifter 250 iselectrically connected to the in-phase mixer 246, out-of-phase mixer 248and the third frequency source 252.

[0031] In the receiver portion 202, LNA 210 amplifies signals receivedover antenna 200 and sends the amplified output to BPF 212. BPF 212rejects all or substantially all signals that are outside the tuningband of the receiver portion 202 (i.e., BPF 212 receives signals withina first frequency band) and passes the signals within the tuning band tomixer 214.

[0032] Mixer 214 downconverts (i.e., demodulates) the received signalsto intermediate frequencies (such as very high frequency “VHF”), withthe first frequency source 208, and sends the downconverted signals tothe IF filter 216. The IF filter 216 removes unwanted out-of-bandsignals that have been downconverted along with the received signal. TheIF filter 216 is followed by AGC amplifier 218, which provides aconstant or substantially constant input to the quadrature demodulator220. As an example, the AGC amplifier 218 may accommodate variablereceived power at the antenna 200 of 90 dB dynamic range. The quadraturedemodulator 220 produces a complex baseband signal having I and Qcomponents by downconverting the intermediate signal to basebandutilizing the second frequency source 244, in-phase mixer 238,out-of-phase mixer 240 and 90° phase shifter 242.

[0033] In the transmitter portion 204, the quadrature modulator 222modulates the incoming I and Q components of a complex baseband signalto a VHF intermediate frequency. The modulation is performed byutilizing the third frequency source 252, in-phase mixer 246,out-of-phase mixer 248, 90° phase shifter 250 and combiner 254. Thequadrature modulator 222 is followed by the AGC amplifier 224 thatprovides a linear variable output power at the antenna 200.

[0034] The IF filter 226 follows the AGC amplifier 224. The IF filter226 reduces the out-of-band noise and spurious signals. The IF filter226 is followed by mixer 228 that modulates the IF signal up to thedesired transmit frequency (i.e., a second frequency band), such asultra high frequency “UIF” or radio frequency “RF” utilizing the firstfrequency source 208. The output from mixer 228 is processed by imagereject BPF 230. The BPF 230 rejects the image frequency (such as higherorder harmonics) from the signal output from mixer 208, and passes orsubstantially passes the entire range of transmit frequencies.

[0035] The pre-driver amplifier 232 follows the image reject BPF 230.The pre-driver amplifier 232 boosts the level of the transmit signalfrom the image reject BPF 230 to a level high enough to drive the poweramplifier 236. The BPF 234 follows the pre-driver amplifier 232. The BPF234 passes the entire range or substantially the entire range oftransmit frequencies, but attenuates harmonic frequencies generated bythe pre-driver amplifier 232. The BPF 234 is configured to have low lossat transmit frequencies, but high attenuation at harmonic frequencies.As an example, the BPF 234 may be a ceramic or surface acoustic wave“SAW” filter. The power amplifier 236 follows the BPF 234. The poweramplifier 236 boosts the level of the transmit signal to the desiredoutput power and sends the signal to the antenna 200 via the duplexer206.

[0036] The undesired signal detector 106, FIG. 1, monitors the receivedsignals at the output of the receiver chain after demodulation, viasignal path 238 to detect if an undesired signal is present in thereceived frequency band at the receiver portion 202. The undesiredsignal detector 106, FIG. 1, outputs a conditional signal indicative ofthe presence of an undesired signal within the frequency band of signalsreceived at the receiver portion 202. The conditional signal is input tothe controller 110 via signal path 116. The controller 110 responsive towhether an undesired signal is present dynamically varies, sets oradjusts the current from the power source 108, FIG. 1, via signal path118, for the first frequency source 208, FIG. 2, second frequency source244 and third frequency source 252.

[0037] The frequency sources in this example implementation, includingthe first frequency source 208, second frequency source 244 and thirdfrequency source 252 are typically implemented in the form of voltagecontrolled oscillators “VCOs”. Additionally, the operating current foreach of the first frequency source 208, second frequency source 244 andthird frequency source 252 may be separately set or adjusted bycontroller 110 because of the different phase noise requirements of eachof these frequency sources.

[0038] As an example, the phase noise requirement for the firstfrequency source 208 is typically more stringent than that for thesecond frequency source 244 because second frequency source 244, unlikethe first frequency source 208, is downstream from the IF filter 216,and the IF filter 216 helps attenuate any undesired signals that arepresent before the undesired signals are able to mix with the frequencyreference signal from the second frequency source 244. Additionally,since third frequency source 252 is part of the transmitter portion 204of the transceiver 106, the need to maintain a low phase noise toeliminate an in-band undesired signal is not present. Moreover, thephase noise requirement is dominated by the adjacent channel power ratio“ACPR” specification, which is less stringent than that imposed on thefrequency sources in the receiver portion 202. As another example, in awireless CDMA system, the ACPR specification typically imposes a phaserequirement of about −98 dBc/Hz whereas the phase noise requirement fora local oscillator in the receiver portion may be −138 dBc/Hz.

[0039] However, it is appreciated that alternative implementations arepossible in which some or all of the frequency sources are dynamicallyadjusted together, and in which only one or some or all of the frequencysources in the transceiver 104 are dynamically adjusted responsive tothe presence of an undesired signal. In another example implementation,only the operating current for first frequency source 208 is dynamicallyadjusted responsive to the presence of an undesired signal. In stillanother example implementation, only the operating currents for thefirst frequency source 208 and second frequency source 244 aredynamically adjusted responsive to the presence of an undesired signal.Also, additional implementations are possible in where the controller110 is embodied in the form of hardware (such as a digital signalprocessing “DSP” chip or application specific integrated circuit “ASIC”)or via software 256 embedded in the controller 110.

[0040]FIG. 3 is a plot of signal amplitude versus frequency showing theinterference effect of an undesired signal 300 (also known as a jammersignal) at frequency “f_(jammer)” 302 within the frequency band 304 ofreceived signals 306 at the transceiver 104, FIG. 2. Frequency band 304,FIG. 3, illustrates the frequency band of received signals 306 at thetransceiver 104, FIG. 2 centered on a desired received signal atfrequency “f₀” 308. The undesired signal 300 is shown at a frequency 302above the desired received signal frequency 308. The frequency envelope310 from the undesired signal 300 is shown overlapping 312 andinterfering within the frequency band 304 of received signals 306 at thetransceiver 104, FIG. 1.

[0041]FIG. 4 is a flow chart of an example process performed by the SCS102 of FIG. 1 in controlling at least one frequency source 112. Theprocess begins in step 400, FIG. 4, and continues to decision step 402.In step 400, the transceiver 104, FIG. 1, receives a frequency band ofsignals received at the receiver portion 202, FIG. 2, of the transceiver104 and the undesired signal detector 106, FIG. 1, produces a conditionsignal indicative of the presence of an undesired signal within thefrequency band of signals received at a receiver portion 202, FIG. 2. Indecision step 402, FIG. 4, the SCS 102, FIG. 1, then receives thecondition signal, via signal path 116, and determines the presence of anundesired signal within the frequency band of signals received at areceiver portion 202, FIG. 2, with the controller 110. If the SCS 102,FIG. 1, determines that there is no undesired signal present, theprocess continues to step 404, FIG. 4. In step 404, the controller 110,FIG. 1, sets the amount of current supplied to at least one frequencysource 112 in the transceiver 104, by the power source 108, to apredetermined current level “C1” and the process ends in step 406, FIG.4.

[0042] If instead the SCS 102, FIG. 1, determines that there is anundesired signal present, the process continues to decision step 408. Indecision step 408, the SCS 102, FIG. 1, determines whether the relativestrength of the undesired signal with respect to the other receivedsignals at the transceiver 104 is available with the controller 11( ).If the SCS 102 determines that the relative strength is not availablethe process continues to step 410, FIG. 4. In step 410, the controller110, FIG. 1, sets the amount of current supplied to at least onefrequency source 112, by the power source 108, to a second current level“C2” above C1 and the process ends in step 406, FIG. 4.

[0043] If instead the SCS 102, FIG. 1, determines that the relativestrength is available, the process continues to step 412, FIG. 4. Instep 412, the controller 110, FIG. 1, determines the relative strengthand utilizes a lookup table or processor unit, in step 414, to determinea third current level “C3” above C1 to supply to the at least onefrequency source 112. The process then continues to step 416, FIG. 4. Instep 416, the controller 110, FIG. 1, sets the amount of currentsupplied to the at least one frequency source 112, by the power source108, to C3 and the process ends in step 406, FIG. 4.

[0044]FIG. 5 is a flow chart of an example process performed by the SCS102 of FIG. 1 in controlling multiple frequency sources. The processbegins in step 500, FIG. 5, and continues to decision step 502. In step500, the transceiver 104, FIG. 1, receives a frequency band of signalsreceived at the receiver portion 202, FIG. 2, of the transceiver 104,FIG. 2, and the undesired signal detector 106, FIG. 1, produces acondition signal indicative of the presence of an undesired signalwithin the frequency band of signals received at a receiver portion 202,FIG. 2. In decision step 502, FIG. 5, the SCS 102, FIG. 1, then receivesthe condition signal, via signal path 116, and determines the presenceof an undesired signal within the frequency band of signals received ata receiver portion 202, FIG. 2, with the controller 110. If the SCS 102,FIG. 1, determines that there is no undesired signal present, theprocess continues to step 504, FIG. 5. In step 504, the controller 110,FIG. 1, sets the amount of current supplied by the power source 108 tothe front end frequency source 208, FIG. 2, in the receiver portion 202of the transceiver 104 to a predetermined current level “C1” and theprocess continues to decision step 506, FIG. 5. In decision step 506,the controller 110, FIG. 1, determines whether to set the back endfrequency source 244, FIG. 2, in the receiver portion 202. If thecontroller 110 decides to set the back end frequency source 244, theprocess continues to step 508, FIG. 5, and the controller 110, FIG. 1,sets back end frequency source 244, FIG. 2, to a second predeterminedcurrent level “C2” and the process continues to decision step 510, FIG.5. If instead the controller 110, FIG. 1, decides not to set the backend frequency source 244, FIG. 2, the process continues to decision step510, FIG. 5.

[0045] In decision step 510, the controller 110, FIG. 1, determineswhether to set the current on the frequency sources in the transmitterportion 204, FIG. 2. If the controller 110 decides to set thetransmitter portion 204 frequency sources, the process continues to step512, FIG. 5, and the controller 110 sets the front end frequency source208 to a third predetermined current level “C3” and the processcontinues to decision step 514, FIG. 5. If instead the controller 110,FIG. 1, decides not to set the frequency sources in the transmitterportion 204, FIG. 2, the process ends in step 516, FIG. 5.

[0046] In decision step 514, the controller 110, FIG. 1, determineswhether to set the current on the back end frequency source 252, FIG. 2,in the transmitter portion 204. If the controller 110 decides to set thetransmitter portion 204 back end frequency source 252, the processcontinues to step 518, FIG. 5, and the controller 110 sets the back endfrequency source 252 to a fourth predetermined current level “C4” andthe process ends in step 516, FIG. 5. If instead the controller 110,FIG. 1, decides not to set the back end frequency source 252, FIG. 2,the process ends in step 516, FIG. 5.

[0047] If in decision step 502 the SCS 102, FIG. 1, determines thatthere is an undesired signal present, the process continues to decisionstep 520, FIG. 5. In decision step 520, the SCS 102, FIG. 1, determineswith the controller 110 whether the relative strength of the undesiredsignal with respect to the other received signals at the transceiver 104is available. If the SCS 102 determines that the relative strength isnot available the process continues to step 522, FIG. 5. In step 522,the controller 110, FIG. 1, sets the amount of current supplied by thepower source 108 to the front end frequency source 208, FIG. 2, in thereceiver portion 202 of the transceiver 104 to a current level “C5”above C1 and the process continues to decision step 524, FIG. 5. Indecision step 524, the controller 110, FIG. 1, determines whether to setthe back end frequency source 244, FIG. 2, in the receiver portion 202.If the controller 110 decides to set the back end frequency source 244,the process continues to step 526, FIG. 5, and the controller 110, FIG.1, sets back end frequency source 244, FIG. 2, to a current level “C6”above C2 and the process continues to decision step 528, FIG. 5. Ifinstead the controller 110, FIG. 1, decides not to set the back endfrequency source 244, FIG. 2, the process continues to decision step528, FIG. 5.

[0048] In decision step 528, the controller 110, FIG. 1, determineswhether to set the current on the frequency sources in the transmitterportion 204, FIG. 2. If the controller 110 decides to set thetransmitter portion 204 frequency sources, the process continues to step530, FIG. 5, and the controller 110 sets the front end frequency source208 to a current level “C7” above C3 and the process continues todecision step 532, FIG. 5. If instead the controller 110, FIG. 1,decides not to set the frequency sources in the transmitter portion 204,FIG. 2, the process ends in step 516, FIG. 5.

[0049] In decision step 532, the controller 110, FIG. 1, determineswhether to set the current on the back end frequency source 252, FIG. 2,in the transmitter portion 204. If the controller 110 decides to set thetransmitter portion 204 back end frequency source 252, the processcontinues to step 534, FIG. 5, and the controller 110 sets the back endfrequency source 252 to a current level “C8” above C4 and the processends in step 516, FIG. 5. If instead the controller 110, FIG. 1, decidesnot to set the back end frequency source 252, FIG. 2, the process endsin step 516, FIG. 5.

[0050] If instead the SCS 102, FIG. 1, in decision step 520, FIG. 5,determines that the relative strength is available, the processcontinues to step 536. In step 536, the controller 110, FIG. 1,determines the relative strength and utilizes a lookup table orprocessor unit, in step 538, to determine a current level “C9” above C1to supply to the front end frequency source 208, FIG. 2 of the receiverportion 202 of the transceiver 104. The process then continues to step540, FIG. 5. In step 540 the controller 110, FIG. 1, sets the amount ofcurrent supplied by the power source 108 to the front end frequencysource 208, FIG. 2, to a current level “C9” above C1 from the lookuptable or processor unit and the process continues to decision step 542,FIG. 5. In decision step 542, the controller 110, FIG. 1, determineswhether to set the back end frequency source 244, FIG. 2, in thereceiver portion 202. If the controller 110 decides to set the back endfrequency source 244, the process continues to step 544, FIG. 5, and thecontroller 110, FIG. 1, sets the back end frequency source 244, FIG. 2,to a current level “C10” above C2 from the lookup table or processorunit and the process continues to decision step 546, FIG. 5. If insteadthe controller 110, FIG. 1, decides not to set the back end frequencysource 244, FIG. 2, the process continues to decision step 546, FIG. 5.

[0051] In decision step 546, the controller 110, FIG. 1, determineswhether to set the current on the frequency sources in the transmitterportion 204, FIG. 2. If the controller 110 decides to set thetransmitter portion 204 frequency sources, the process continues to step548, FIG. 5, and the controller 110 sets the front end frequency source208 to a current level “C11” above C3 from the lookup table or processorunit and the process continues to decision step 550, FIG. 5. If insteadthe controller 110, FIG. 1, decides not to set the frequency sources inthe transmitter portion 204, FIG. 2, the process ends in step 516, FIG.5.

[0052] In decision step 550, the controller 110, FIG. 1, determineswhether to set the current on the back end frequency source 252, FIG. 2,in the transmitter portion 204. If the controller 110 decides to set thetransmitter portion 204 back end frequency source 252, the processcontinues to step 552, FIG. 5, and the controller 110 sets the back endfrequency source 252 to a current level “C12” above C4 from the lookuptable or processor unit and the process ends in step 516, FIG. 5. Ifinstead the controller 110, FIG. 1, decides not to set the back endfrequency source 252, FIG. 2, the process ends in step 516, FIG. 5.

[0053] It is appreciated that the controller 110, FIG. 1, may beselectively implemented in software, hardware, or a combination ofhardware and software. For example, the elements of the controller 110may be implemented in software 258, FIG. 2, stored in a memory locatedin a controller 110. The software 258 configures and drives thecontroller 110 and performs the processes illustrated in FIG. 4 and FIG.5.

[0054] The software 258 includes an ordered listing of executableinstructions for implementing logical functions. The software 258 may beembodied in any computer-readable medium, or computer bearing medium,for use by or in connection with an instruction execution system,apparatus, or device, such as a computer-based system,processor-containing system, or other system that may selectively fetchthe instructions from the instruction execution system, apparatus, ordevice and execute the instructions. In the context of this document, a“computer-readable medium” is any means that may contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The computer readable medium may be for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, device, or propagation medium. Morespecific examples (a non-exhaustive list) of the computer-readablemedium would include the following: an electrical connection(electronic) having one or more wires, a portable computer diskette(magnetic), a RAM (electronic), a read-only memory “ROM” (electronic),an erasable programmable read-only memory (EPROM or Flash memory)(electronic), an optical fiber (optical), and a portable compact discread-only memory “CDROM” (optical).

[0055] An example implementation of the processes described in FIG. 4and FIG. 5 may employ at least one computer-readable signal bearingmedium (such as the internet, magnetic storage medium, such as floppydisks, or optical storage, such as compact disk (CD/DVD), biological, oratomic data storage medium). In yet another example implementation, thecomputer-readable signal-bearing medium comprises a modulated carriersignal transmitted over a network comprising or coupled with a diversityreceiver apparatus, for instance, one or more telephone networks, alocal area network, the Internet, and wireless network. An exemplarycomponent of such embodiments is a series of computer instructionswritten in or implemented with any number of programming languages. Notethat the computer-readable medium may even be paper or another suitablemedium upon which the program is printed, as the program can beelectronically captured, via for instance optical scanning of the paperor other medium, then compiled, interpreted or otherwise processed in asuitable manner if necessary, and then stored in a computer memory.

[0056]FIG. 6 is a block diagram of another example implementation of aSCS 600 within a communication device 602. The communication device 602includes the SCS 600, an undesired signal detector 604, a transceiver606 and a power source 608. The SCS includes a controller 610 and thetransceiver 606 includes a frequency source 612. In this exampleimplementation the SCS 600 is electrically connected to the undesiredsignal detector 604 and the power source 608. The SCS 600 is alsoelectrically connected externally to the transceiver 606.

[0057] While various embodiments of the application have been described,it will be apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible that are within the scopeof this invention. Accordingly, the invention is not to be restrictedexcept in light of the attached claims and their equivalents.

What is claimed is:
 1. A system comprising: a condition signalindicative of the presence of an undesired signal within a frequencyband of signals received at a receiver; and a controller that adjusts afrequency source responsive to the condition signal.
 2. The system ofclaim 1 wherein the controller adjusts an operating current of thefrequency source.
 3. The system of claim 2 wherein the frequency sourceis an oscillator.
 4. The system of claim 2 wherein the operating currentof the frequency source is dynamically adjusted by the controllerresponsive to the presence of the undesired signal.
 5. The system ofclaim 4 wherein the operating current of the frequency source is set ata default level optimized for the presence of the undesired signal. 6.The system of claim 5 wherein the operating current of the frequencysource is reduced from the default level for the absence of theundesired signal.
 7. The system of claim 1 wherein the receiver is partof a transceiver.
 8. The system of claim 7 wherein the transceiverincludes a transmitter portion, and an operating current of anotherfrequency source in the transmitter portion is dynamically adjustedresponsive to the presence of the undesired signal.
 9. The system ofclaim 8 wherein the operating current of the other frequency source isset at a default level optimized for the presence of the undesiredsignal.
 10. The system of claim 9 wherein the operating current of theother frequency source is reduced from the default level for the absenceof the undesired signal.
 11. The system of claim 8 wherein thetransceiver is a spread spectrum transceiver.
 12. The system of claim 8wherein the transceiver is a time domain multiple access transceiver.13. The system of claim 8 wherein the transceiver is an analogmodulation transceiver.
 14. The system of claim 12 wherein thetransceiver is a frequency modulation (FM) transceiver.
 15. The systemof claim 1 wherein the receiver includes a superheterodyne receiverhaving a ultra-high frequency (UHF) frequency source, and an operatingcurrent of the UHF frequency source is dynamically adjusted responsiveto the presence of the undesired signal.
 16. The system of claim 15wherein the superheterodyne receiver also has a very-high frequency(VHF) frequency source, the operating current of the VHF frequencysource is dynamically adjusted responsive to the presence of theundesired signal.
 17. The system of claim 1 wherein the receiver is in awireless communication device.
 18. The system of claim 1 wherein thecontroller varies a plurality of frequency sources responsive to thecondition signal.
 19. The system of claim 18 wherein the controllervaries the operating currents of the plurality of frequency sources. 20.The system of claim 19 wherein each frequency source of the plurality offrequency sources is an oscillator.
 21. The system of claim 19 whereinthe operating currents of the plurality of frequency sources aredynamically varied by the controller responsive to the presence of theundesired signal.
 22. The system of claim 21 wherein the operatingcurrent of the plurality of frequency sources is set at a default leveloptimized for the presence of the undesired signal.
 23. The system ofclaim 22 wherein the operating current of the plurality of frequencysource is reduced from the default level for the absence of theundesired signal.
 24. The system of claim 18 wherein the controllervaries the operating current for the plurality of frequency sourcesseparately.
 25. A system comprising: a condition signal indicative ofthe presence of an undesired signal within a frequency band of signalsreceived at a receiver having a front-end and a back-end; and acontroller that varies a frequency source responsive to the conditionsignal.
 26. The system of claim 25 wherein the frequency source isconnected via a signal path to the front-end of the receiver.
 27. Thesystem of claim 26 wherein the frequency source is an oscillator. 28.The system of claim 26 wherein the frequency source is connected by thesignal path to a mixer in the front-end of the receiver.
 29. The systemof claim 28 wherein the frequency source is an oscillator.
 30. Thesystem of claim 25 wherein the receiver is part of a transceiver. 31.The system of claim 30 wherein the transceiver includes a transmitterportion, and the frequency source is connected by a second signal pathto the transmitter portion.
 32. The system of claim 31 wherein thetransmitter portion has a front-end and a back-end and the frequencysource is connected by the second signal path to the front-end of thetransmitter portion.
 33. The system of claim 32 wherein the frequencysource is connected by the signal path to a mixer in the front-end ofthe transmitter portion.
 34. The system of claim 33 wherein thefrequency source is an oscillator.
 35. The system of claim 25 whereinthe frequency source is connected by a signal path to the back-end ofthe receiver.
 36. The system of claim 35 wherein the frequency source isan oscillator.
 37. The system of claim 35 wherein the frequency sourceis connected by a signal path to a mixer in the back-end of thereceiver.
 38. The system of claim 37 wherein the frequency source is anoscillator.
 39. The system of claim 25 wherein the receiver is part of atransceiver.
 40. The system of claim 39 wherein the transceiver includesa transmitter portion, and the frequency source is connected by a secondsignal path to the transmitter portion.
 41. The system of claim 40wherein the transmitter portion has a front-end and a back-end, and thefrequency source is connected by the second signal path to the back-endof the transmitter.
 42. The system of claim 41 wherein the frequencysource is connected by the signal path to a mixer in the back-end of thetransmitter.
 43. The system of claim 42 wherein the frequency source isan oscillator.
 44. A method comprising: determining the presence of anundesired signal within a frequency band of signals received at areceiver; and adjusting a frequency source responsive to the presence ofthe undesired signal.
 45. The method of claim 44 wherein the step ofvarying further includes varying an operating current of the frequencysource.
 46. The method of claim 45 wherein the frequency source is anoscillator.
 47. The method of claim 45 wherein the varying the operatingcurrent is dynamic.
 48. The method of claim 47 further including:setting the operating current of the frequency source to a default leveloptimized for the presence of the undesired signal; and reducing theoperating current upon determining the absence of the undesired signal.49. The method of claim 44 wherein the receiver is part of atransceiver.
 50. The method of claim 49 further comprising dynamicallyadjusting the operating current of at least one local oscillator in thereceiver.
 51. The method of claim 44 further comprising dynamicallyadjusting the operating current of the frequency source in a transmitterportion of the transceiver responsive to the presence of the undesiredsignal.
 52. The method of claim 44 further comprising dynamicallyadjusting the operating current of a VHF local oscillator in asuperheterodyne receiver responsive to the presence of the undesiredsignal.
 53. The method of claim 44 further comprising dynamicallyadjusting the operating current of a UHF local oscillator in asuperheterodyne receiver responsive to the presence of the undesiredsignal.
 54. The method of claim 44 further including varying a pluralityof frequency sources responsive to the presence of the undesired signal.55. The method of claim 54 wherein the step of varying includesseparately varying the operating currents of the plurality of frequencysources responsive to the presence of the undesired signal.
 56. Themethod of claim 55 wherein the receiver is part of a transceiver.